[Technical Field]
[0001] The present disclosure relates to a physically pretreated biomass composition, which
comprises a high concentration of a biomass substrate, for enabling chemical treatment,
and a preparation method thereof.
[Background Art]
[0002] Lignocellulosic biomass is composed of a non-degradable structure of cellulose, hemicellulose,
and lignin. In order to use lignocellulosic biomass as a sustainable supply source
of biofuels and biochemicals, it must be economically converted into useful intermediates
such as sugar. It can be converted into fermentable sugar after passing through physical
pretreatment, chemical pretreatment, and biological pretreatment that are suitable
for lignocellulosic biomass properties.
[0003] The above pretreatment processes are an essential step in converting lignocellulosic
biomass into sugar, but they have the highest operating cost among all processes.
One of the most important methods to reduce such pretreatment costs is to increase
biomass loading amounts and minimize solvent use, and through this, it can not only
reduce the size of upstream processes and investment costs, but also it can reduce
the costs for solid-liquid separation of downstream processes and solvent recycling.
[0004] However, when conventional techniques are used, high solid concentrations (high concentration
substrate conditions) can have negative effects due to inadequate mixing, resulting
in low sugar conversion. Specifically, in order to obtain sufficient mixing under
high concentration substrate conditions, a special stirring method must be applied,
and in this case, high power consumption is required. In addition, biomass slurry
under such high concentration substrate conditions must be transported through various
unit processes during the process, and at high solid concentrations, these mixing
and transport problems become difficult because the slurry is thick and pasty. Therefore,
the fluidity and flowability of the biomass slurry under a high concentration substrate
condition greatly affect equipment that is used such as reactors and pumps, and it
is a main factor for the increase in investment costs.
[0005] In addition, in case of herbaceous biomass, because of the remarkably low raw material
density characteristics, the moisture content relative to the biomass volume is extremely
limited at a solid (biomass) concentration of 10% or more; that is, because the solvent
cannot sufficiently moisten the biomass, the chemical pretreatment reaction cannot
proceed.
[Disclosure]
[Technical Problem]
[0006] In order to solve the problems above, biomass treatment methods using various physical
pretreatment methods are being studied, and Korean Patent No.
10-1171922 discloses a process of reducing the size of initial biomass by stone grinding, mechanical
ripping, tearing, and pin grinding for the pretreatment of biomass and then decomposing
biomass through electron beam irradiation. However, in this case, two pretreatment
processes are performed, and above all, electron beam irradiation has high energy
consumption, and thus there is a problem in that it consumes more energy than the
energy generated through actual biomass decomposition, and therefore a solution therefor
is required.
[Technical Solution]
[0007] An object of the present disclosure is to provide a physically pretreated biomass
composition, wherein a concentration of the biomass substrate is in a range of 20%
(w/w) to 30% (w/w) and a viscosity of the composition is in a range of 0.01 [Pa·s]
to 10 [Pa·s].
[0008] Another object of the present disclosure is to provide a method for preparing a biomass
composition, comprising (a) physically pretreating biomass; and (b) mixing the physically
pretreated biomass and a solvent at a ratio (w/w) of 20:80 to 30:70 and stirring,
wherein a concentration of the biomass is in a range of 20% to 30% (w/w) and a viscosity
of the composition is in a range of 0.01 [Pa·s] to 10 [Pa·s].
[Advantageous Effect]
[0009] Through specific physical pretreatment (attrition milling) of herbaceous biomass,
the physically pretreated biomass composition of the present disclosure has fluidity/flowability
at a substrate concentration of biomass of 20% (w/w) (biomass:solvent = 1:4) or above,
and thus the pretreatment cost may be reduced, and it is very useful in biomass treatment
processes.
[Brief Description of Drawings]
[0010]
FIG. 1 is a diagram showing the mixing property of a physically pretreated biomass
composition having a concentration of the biomass substrate of 20% (w/w).
FIG. 2 is a diagram showing the rheometer measurement conditions for measuring the
rheological properties of a physically pretreated biomass slurry.
FIG. 3 is a graph showing viscosity versus shear rate of a physically pretreated biomass
slurry (a: corn stover, b: wheat straw, c: Miscanthus sacchariflorus, d: rice straw, and e: bagasse).
FIG. 4 is a graph showing the yield stress of a physically pretreated biomass slurry
(a: corn stover, b: wheat straw, c: Miscanthus sacchariflorus, d: rice straw, and e: bagasse).
FIG. 5 is a graph showing the flow stress of a physically pretreated biomass slurry
(a: corn stover, b: wheat straw, c: Miscanthus sacchariflorus, d: rice straw, and e: bagasse).
[Best Mode for Carrying Out the Invention]
[0011] Hereinafter, the present disclosure will be described in detail.
[0012] Meanwhile, each description and embodiment disclosed in the present disclosure may
be applied to each other description and embodiment. That is, all combinations of
the various elements disclosed in this application fall within the scope of the present
disclosure. In addition, it cannot be said that the scope of the present disclosure
is limited by the specific descriptions described below. In addition, those skilled
in the art can recognize or identify a number of equivalents for a particular aspect
described in the present disclosure using only conventional experimentation. In addition,
such equivalents are intended to be included in the present disclosure.
[0013] An aspect of the present disclosure to achieve the above objects provides a physically
pretreated biomass composition, wherein a concentration of the biomass is in a range
of 20% to 30% (w/w) and a viscosity of the composition is in a range of 0.01 [Pa·s]
to 10 [Pa·s].
[0014] As used herein, the term "biomass" collectively refers to plants, which synthesize
organic matter by receiving solar energy, and biological organisms such as animals,
microorganisms,
etc. using plants as food, and in ecological perspective, biomass refers to all species
belonging to biological organisms or one species of animals and plants expressed in
biomass within a unit area or unit volume of habitat. In addition, biomass is generally
irrelevant to life and death and is used in a broad sense, and biomass includes cedar
wood, charcoal, biogas,
etc., and in industry, organic waste is also included in biomass.
[0015] The biomass is largely classified as cultivation resource-based or waste resource-based
biomass depending on the raw material, and the cultivation resource-based biomass
can be classified into sugar-based, starch-based, cellulose-based, carbohydrate-based,
oil-based, freshwater-based, marine-based, microbe-based,
etc. depending on the origin. The biomass of the physically pretreated biomass composition
of the present disclosure may be cellulose-based biomass including tree-based, herbaceous-based,
and pasturage-based biomass, and may be specifically herbaceous biomass, bus it not
limited thereto.
[0016] In addition, as used herein, the term "herbaceous biomass" collectively refers to
rice, leguminous crops, and remnants thereof used for the production of food or feed
other than trees growing on grassland, and for example, the herbaceous biomass may
be derived from corn stover, wheat straw,
Miscanthus sacchariflorus, rice straw, or bagasse, but is not limited thereto.
[0017] As used herein, the term "pretreatment" collectively refers to a process that allows
improving the rate and yield of biomass enzyme hydrolysis. The ultimate purpose of
pretreatment is to increase the accessibility of enzymes by reducing the crystallinity
of non-degradable structures of cellulose,
etc., and to increase the amount of effective enzymes by increasing the specific surface
area of biomass. Since the production cost of biofuel is determined according to the
degree of efficiency of the pretreatment process, the pretreatment process is regarded
as an essential step for converting biomass to biofuel.
[0018] The pretreatment method can be largely divided into physical, chemical, and biological
methods according to the treatment method. Representative physical methods include
milling or steam explosion; chemical methods include dilute acid pretreatment, and
soaking in aqueous ammonia (SAA) and ammonia recycled percolation (ARP) which use
ammonia as a catalyst; and biological methods include methods using microorganisms
such as molds,
etc.
[0019] The physical pretreatment method of the present disclosure may be the milling treatment
of biomass, and the milling may include one or more milling treatments of attrition
milling, grinder milling, hammer milling, or cutter milling. Specifically, the physical
pretreatment may include the attrition milling treatment using attrition mill, but
is not limited thereto.
[0020] For the purpose of the present disclosure, the biomass composition may refer to the
one that is physically pretreated, and through the physical pretreatment, a composition
suitable for chemical and biological pretreatments may be provided.
[0021] The physically pretreated biomass composition of the present disclosure may include
a high concentration of biomass. The biomass may mean a biomass substrate, a solid
content thereof,
etc., but is not limited thereto. Including a high concentration of biomass may mean
increasing biomass loading in the biomass composition and minimizing solvent use,
and it may be to increase the solid-liquid ratio (solid / (solid+liquid)) or biomass
substrate ratio (biomass / (biomass+liquid)) in the biomass composition expressed
as the concentration of the biomass substrate, but is not limited thereto. In addition,
the biomass composition may be a biomass slurry.
[0022] In case of herbaceous biomass, due to the significantly low density properties of
a raw material, when the biomass concentration is 10% or more, the amount of moisture
relative to the volume of biomass is extremely limited; that is, the solvent cannot
sufficiently moisten the biomass, and thus the chemical pretreatment reaction cannot
proceed. In addition, when the concentration of the biomass substrate of the biomass
composition is less than 20%, the size of the reactor which is used during the biomass
treatment process is increased, or the final sugar concentration is low, and thus
a concentration process is required, resulting in additional costs. When the concentration
of the biomass substrate is greater than 30%, there is a problem that it is difficult
to implement during a process in a simple stirring method (using an impeller).
[0023] The concentration of biomass in the physically pretreated biomass composition of
the present disclosure may specifically be 10% to 40% (w/w), 10% to 35% (w/w), 10%
to 30% (w/w), 15% to 40% (w/w), 15% to 35% (w/w), 15% to 30% (w/w), 20% to 40% (w/w),
20% to 35% (w/w), or 20% to 30% (w/w), but is not limited thereto.
[0024] As used herein, the term "viscosity" refers to resistance to the flow of fluid and
is also referred to as internal friction because it is the frictional force that appears
inside a moving liquid or gas. That is, it is the sticky property of the liquid. Viscosity
is usually regarded as stickiness or internal resistance to the flow of a fluid or
gas and can be said to be a measure of resistance to the flow of a fluid, and generally,
the lower the viscosity of a fluid, the higher the flowability or fluidity. The unit
of viscosity is Pa·s (N·s/m
2 = kgf·s/m
2) in the international unit system, and P (poise; dyn·s/cm
2 = g/cm·s) in the CGS unit system. In addition, viscosity may be used in combination
with viscousness, viscosity coefficient, or viscosity factor. In the present disclosure,
the viscosity was measured under the rheometer condition of a shear rate of 1 to 100
[1/s] and a 4-bladed stirrer (FIG. 2).
[0025] For example, in the present disclosure, it was confirmed that the biomass composition
that was physically pretreated through attrition milling treatment had a low viscosity
and excellent flowability, and mixing and flowing were easy during stirring.
[0026] The viscosity of the physically pretreated biomass composition of the present disclosure
may specifically be 0.05 [Pa·s] to 20 [Pa·s], 0.05 [Pa·s] to 15 [Pa·s], 0.05 [Pa·s]
to 10 [Pa·s], 0.01 [Pa·s] to 20 [Pa·s] , 0.01 [Pa·s] to 15 [Pa·s], or 0.01 [Pa·s]
to 10 [Pa·s], but is not limited thereto.
[0027] The yield stress and flow stress of the physically pretreated biomass composition
having a concentration of the biomass substrate of 20% to 30% (w/w) may be 1 to 100
[pa].
[0028] As used herein, the term "stress" is a force per unit area acting inside an object,
which usually occurs when an external force is applied and the object deforms to return
the shape to its original shape. Therefore, when an object is deformed by applying
stress, it is deformed (elastic deformation) in proportion to the stress when the
stress is small, and when the stress is removed, it returns to its original state.
However, when the stress exceeds a certain limit, there is a case where the deformation
rapidly increases, and this limit stress is called the "yield stress" of the material.
Above the yield stress, the object does not return to its original shape. In addition,
"flow stress" is also referred to as flow stress or deformation stress, and means
external stress required to plastically deform a material. In the present disclosure,
if the yield stress and the flow stress of the physically pretreated biomass composition
are low, it may have fluidity even when a small force is applied, which means that
the flowability and fluidity of the biomass composition are excellent.
[0029] Specifically, the physically pretreated biomass composition having a concentration
of the biomass substrate of 20% to 30% (w/w) may have a yield stress or flow stress
in a range of 1 [pa] to 100 [pa], 1 [pa] to 80 [pa], 1 [pa] to 60 [pa], 1 [pa] to
40 [pa], 1 [pa] to 20 [pa], 3 [pa] to 100 [pa], 3 [pa] to 80 [pa], 3 [pa] to 60 [pa],
3 [pa] to 40 [pa], or 3 [pa] to 20 [pa], but is not limited thereto.
[0030] In addition, the average particle size of the biomass of the present disclosure may
be 10 µm to 50 µm, or it may be a physically treated biomass composition of which
the density is 0.4 g/mL to 0.6 g/mL.
[0031] As used herein, the term "particle size" refers to the size of powder and granule,
and unlike the particle diameter which usually represents the size of a particle as
a diameter, the particle size also includes indirect indications such as specific
surface area,
etc. In case of a perfect spherical shape, a simple relationship is established between
the particle diameter and other particle sizes, but it is generally difficult to determine
the particle size in one word, and it is expressed as any average representative length,
such as an average diameter (average value of lengths in two or more directions) or
an equivalent diameter (assuming that a polyhedron is of some simple shape and has
a representative length).
[0032] In addition, as used herein, the term "density" is a value obtained by dividing the
mass of a substance by a volume, and every substance has a unique value. The unit
of density is mainly g/mL, g/cm
3,
etc.
[0033] For example, in the present disclosure, since the average particle size of a biomass
composition that was physically pretreated through attrition milling treatment was
low and the density was high such that the volume occupied by the biomass composition
of the same weight was small, it was confirmed that a relatively small amount of a
solvent could be used.
[0034] The average particle size of the physically pretreated biomass composition of the
present disclosure may specifically be 5 µm to 80 µm, 5 µm to 70 µm, 5 µm to 60 µm,
5 µm to 50 µm, 10 µm to 80 µm, 10 µm to 70 µm, 10 µm to 60 µm, 10 µm to 50 µm, or
15 µm to 50 µm, but is not limited thereto.
[0035] In addition, the density may specifically be 0.4 g/mL to 0.7 g/mL, 0.4 g/mL to 0.65
g/mL, 0.4 g/mL to 0.6 g/mL, 0.45 g/mL to 0.7 g/mL, 0.45 g/mL to 0.65 g/mL, 0.45 g/mL
to 0.6 g/mL, 0.5 g/mL to 0.7 g/mL, 0.5 g/mL to 0.65 g/mL, or 0.5 g/mL to 0.6 g/mL,
but is not limited thereto.
[0036] In addition, the physically pretreated biomass composition of the present disclosure
may include glucose, xylose, lignin, and ash, and may additionally include mannose,
galactose, arabinose,
etc.
[0037] Specifically, based on 100 parts by weight of the biomass composition, glucose may
be included in a range of 25 parts by weight to 55 parts by weight, 25 parts by weight
to 50 parts by weight, 25 parts by weight to 45 parts by weight, 30 parts by weight
to 55 parts by weight, 30 parts by weight to 50 parts by weight, 30 parts by weight
to 45 parts by weight, 35 parts by weight to 55 parts by weight, 35 parts by weight
to 50 parts by weight, or 35 parts by weight to 45 parts by weight, but is not limited
thereto.
[0038] In addition, based on 100 parts by weight of the biomass composition, xylose may
be specifically included in a range of 10 parts by weight to 40 parts by weight, 10
parts by weight to 35 parts by weight, 10 parts by weight to 30 parts by weight, 15
parts by weight to 40 parts by weight, 15 parts by weight to 35 parts by weight, or
15 parts by weight to 30 parts by weight, but is not limited thereto.
[0039] In addition, based on 100 parts by weight of the biomass composition, lignin may
be specifically included in a range of 10 parts by weight to 35 parts by weight, 10
parts by weight to 30 parts by weight, 10 parts by weight to 25 parts by weight, 15
parts by weight to 35 parts by weight, 15 parts by weight to 30 parts by weight, or
15 parts by weight to 25 parts by weight, but is not limited thereto.
[0040] In addition, based on 100 parts by weight of the biomass composition, ash may be
specifically included in a range of 1 part by weight to 25 parts by weight, 1 part
by weight to 20 parts by weight, 1 part by weight to 15 parts by weight, 3 parts by
weight to 25 parts by weight, 3 parts by weight to 20 parts by weight, 3 parts by
weight to 15 parts by weight, 5 parts by weight to 25 parts by weight, 5 parts by
weight to 20 parts by weight, or 5 parts by weight to 15 parts by weight, but is not
limited thereto.
[0041] Another aspect of the present disclosure to achieve the above objects provides a
method for preparing a biomass composition, comprising (a) physically pretreating
biomass; and (b) mixing the physically pretreated biomass and a solvent at a ratio
(w/w) of 20:80 to 30:70 and stirring, wherein a concentration of the biomass is in
a range of 20% to 30% (w/w) and a viscosity of the composition is in a range of 0.01
[Pa·s] to 10 [Pa·s]. Specifically, the physical treatment may include attrition mill
treatment, but is not limited thereto.
[0042] The terms "biomass", "physical pretreatment", and "viscosity" are the same as described
above.
[DETAILED DESCRIPTION OF THE INVENTION]
[0043] Hereinafter, the constitution and effects of the present disclosure will be described
in more detail through examples. These examples are only for illustrating the present
disclosure, and the scope of the present disclosure is not limited by the examples.
[0044] Since the physically pretreated biomass composition of the present disclosure has
a low average particle size and a high density by attrition milling treatment, a low
viscosity can be maintained even though it contains a high concentration of a biomass
substrate when preparing a biomass slurry.
[0045] Therefore, it was confirmed that the physically pretreated biomass composition had
excellent flowability and fluidity even when the concentration of the biomass substrate
was 20% (w/w) or more.
Example 1: Preparation of physically pretreated composition of herbaceous biomass
[0046] In order to prepare a physically pretreated herbaceous biomass composition, the following
experiments were performed.
[0047] Specifically, 5 types of herbaceous biomass of corn stover, wheat straw,
Miscanthus sacchariflorus, rice straw, and bagasse were physically pretreated by attrition milling, grinder
milling, hammer milling, or cutter milling method. The attrition milling was performed
for 10 minutes at 300 rpm using an attrition grinder (KHAM-30S, Hankook Mineral Powder,
Co., Ltd.). In addition, the grinder milling, hammer milling, and cutter milling were
performed using a multipurpose grinder (Multi Mill, RD1-15,
). 2 mm screen was used for the cutter milling and hammer milling, and the grinder
milling was treated by adjusting the clearance to be 50 µm.
Example 2: Measurement of particle size and density and composition analysis of pulverized
biomass composition
[0048] The following experiments were performed to determine the particle size, density
and composition of the physically pretreated herbaceous biomass composition.
[0049] Specifically, after tapping for 1 minute using 10 g of the physically pretreated
composition prepared in Example 1 above, the density was measured by determining its
volume (Table 1), and the average particle size of the physically pretreated composition
was measured by dry analysis using a particle size analyzer (Particle size Analysis,
LS 13 220, BECKMAN COULTER™) (Table 2). In addition, the components of the biomass
treated by attrition milling were analyzed by the method of NREL Procedures LAP-002
(Table 3).
[0050] As a result, when treated by the attrition milling, the average particle size was
50 µm or less, and the density was 0.5 g/mL or more, showing a significant difference
in an average particle size and density from other grinding methods. Through this,
it was possible to predict that a relatively small amount of a solvent could be used
due to the significantly low average particle size and high density of the herbaceous
biomass treated by the attrition milling.
[Table 1]
Herbaceous biomass density by grinding method [g/mL] |
|
Corn stover |
Wheat straw |
Miscanthus sacchariflorus |
Rice straw |
Bagasse |
Attrition milling |
0.56 |
0.50 |
0.56 |
0.50 |
0.50 |
Grinder milling |
0.16 |
0.31 |
0.26 |
0.31 |
0.29 |
Hammer milling |
0.18 |
0.20 |
0.26 |
0.20 |
0.19 |
Cutter milling |
0.18 |
0.30 |
0.31 |
0.30 |
0.21 |
[Table 2]
Average particle size of herbaceous biomass depending on grinding method [µm] |
|
Corn stover |
Wheat straw |
Miscanthus sacchariflorus |
Rice straw |
Bagasse |
Attrition milling |
36.2 |
19.3 |
48.1 |
17.5 |
25.9 |
Grinder milling |
281.7 |
770.7 |
719.1 |
480.9 |
205.6 |
Hammer milling |
608.9 |
882.3 |
905.6 |
- |
665.0 |
Cutter milling |
627.6 |
843.5 |
771.4 |
512.8 |
613.1 |
[Table 3]
Composition of attrition milling-treated biomass |
|
Corn stover |
Wheat straw |
Miscanthus sacchariflorus |
Rice straw |
Bagasse |
Glucose |
37.5 |
37.1 |
41.6 |
42.9 |
40.9 |
Xylose |
21.7 |
21.6 |
17.3 |
21.8 |
26.9 |
Mannose |
0.6 |
0.6 |
0.8 |
0.0 |
0.0 |
Galactose |
1.6 |
1.1 |
1.9 |
0.0 |
2.3 |
Arabinose |
2.7 |
2.8 |
3.2 |
2.9 |
1.4 |
Lignin |
19.3 |
21.0 |
21.7 |
17.5 |
20.7 |
Ash |
6.3 |
6.3 |
2.6 |
11.6 |
4.8 |
others |
10.3 |
9.5 |
10.9 |
3.3 |
3.0 |
Total |
100.0 |
100.0 |
100.0 |
100.0 |
100.0 |
Example 3: Evaluation of mixing property of physically pretreated biomass composition
with solvent
[0051] In order to examine the mixing property with a solvent at 20% (w/w), which is a high
concentration substrate condition of the physically pretreated herbaceous biomass,
20 g of water was added to 5 g of milling-treated biomass and stirred (FIG. 1). As
a result, in case of physical pretreatment other than attrition milling, because the
moisture content is extremely limited compared to the volume of biomass as shown in
FIG. 1 due to the significantly low density of raw materials, there was a phenomenon
in which a solvent could not sufficiently moisten the biomass at 20% (w/w). However,
when treated by the attrition milling, it was confirmed that mixing and flow were
easy at a substrate concentration of 20% (w/w) due to smooth stirring.
Example 4: Measurement of rheology property of physically pretreated biomass slurry
[0052] In order to compare and examine the flowability of the pulverized herbaceous biomass,
the rheological properties of the biomass slurry were measured under the conditions
shown in FIG. 2 using a rheometer (Rheometer, MCR702, AntonPaar).
[0053] Specifically, the biomass and water were mixed as shown in Table 4 and stirred for
1 minute, and then the viscosity was measured by the flow test measurement method
under the rheometer measurement conditions of FIG. 2 (shear rate: 1 [1/s] to 100 [1/s],
4-bladed stirrer). As a result, in case of grinder, hammer, and cutter-milled biomass,
rheological measurement could not be performed at 20% (w/w) because there was no movement
as in Example 3, and thus measurement was performed at the maximum substrate concentration
of 10% (w/w) at which measurement was possible.
[Table 4]
Substrate concentration of biomass slurry for viscosity measurement (%, w/w) |
|
Corn stover %(w/w) |
Wheat straw %(w/w) |
Miscanthus sacchariflorus %(w/w) |
Rice straw %(w/w) |
Bagasse %(w/w) |
Attrition milling |
20 |
20 |
20 |
20 |
20 |
Grinder milling |
10 |
10 |
10 |
10 |
10 |
Hammer milling |
10 |
10 |
10 |
10 |
10 |
Cutter milling |
10 |
10 |
10 |
10 |
10 |
[0054] The rheological measurement results of the physically pretreated biomass slurry are
shown in FIG. 3. In the graph of FIG. 3, the x-axis represents the velocity at which
the fluid moves, and it is common that as the velocity of the fluid is increased (the
x-axis becomes greater) by applying a force to the fluid during measurement, viscosity
decreases.
[0055] As a result of the rheological measurement of the physically pretreated biomass slurry
(FIG. 3), when the attrition milling treatment was performed for all of the herbaceous
biomass used in the Examples, even though the substrate concentration was 20% (w/w)
which is higher than 10% (w/w) of the grinder, hammer, and cutter milling, it always
showed a lower viscosity characteristic (y value) at the same x value (when the same
force is applied to the fluid). Therefore, it is judged that the cost of reactor design
and operation can be reduced when using biomass treated by the attrition milling because
mixing and flow are advantageous.
[0056] In addition, after mixing the biomass and water together as shown in FIG. 5 and stirring
for 1 minute, yield stress and flow stress were measured by the yield stress measurement
method of FIG. 2. Among the biomasses treated by the attrition milling, corn stover
and wheat straw were measured at a substrate concentration of 20% (w/w), and in case
of
Miscanthus sacchariflorus, rice straw and bagasse, since the fluidity is high, it is impossible to measure yield
stress and flow stress because a force cannot be applied at a substrate concentration
of 20% (w/w), and thus it was measured by increasing the substrate concentration to
25% (w/w). In addition, in case of grinder, hammer, and cutter-milled biomass, the
rheological measurement could not be performed at 20% (w/w) because there was no movement
as in Example 3, and thus the measurement was performed at the maximum substrate concentration
of 10% (w/w) at which the measurement was possible.
[Table 5]
Substrate concentration of biomass slurry for measuring yield stress and flow stress |
|
Corn stover %(w/w) |
Wheat straw %(w/w) |
Miscanthus sacchariflorus %(w/w) |
Rice straw %(w/w) |
Bagasse %(w/w) |
Attrition milling |
20 |
20 |
25 |
25 |
25 |
Grinder milling |
10 |
10 |
10 |
10 |
10 |
Hammer milling |
10 |
10 |
10 |
10 |
10 |
Cutter milling |
10 |
10 |
10 |
10 |
10 |
[0057] As a result, when the attrition milling was treated for most of the herbaceous biomasses
used in the Examples, it showed lower yield stress and flow stress, even though the
substrate concentration was 20% to 25% (w/w), which was higher than 10% (w/w) of grinder,
hammer, and cutter milling (Table 6, FIG. 4, and FIG. 5). Meanwhile, when the cutter
milling was treated for corn stover and
Miscanthus sacchariflorus biomasses, and when the hammer milling was treated for wheat straw
and Miscanthus sacchariflorus biomasses, yield stress or flow stress was measured to be low compared to when treated
with the attrition milling, and this was measured as such because the concentration
of the biomass substrate that was treated by the cutter milling or hammer milling
was significantly low at 10% (w/w). If the concentration of the substrate is the same,
it can be expected that the yield stress and flow stress of the biomass treated by
the attrition milling are significantly lower than those of the cutter milling or
hammer milling treatment. In addition, the portion where the measured value was not
described was impossible to measure because there was no flowability itself.
[0058] Therefore, in case of the attrition-milled biomass slurry, it is considered to be
advantageous for mixing and flow compared to a grinder, hammer, or cutter-milled biomass
slurry, and it is judged that the cost of reactor design and operation can be reduced.
[0059] In addition,
Miscanthus sacchariflorus, rice straw, and bagasse slurries had a somewhat high slurry substrate concentration
for yield stress and flow stress compared to corn stover and wheat straw slurries
in the attrition milling. Through this, it can be predicted that
Miscanthus sacchariflorus, rice straw, and bagasse had greater liquidity than corn straw and wheat straw.
[Table 6]
|
Corn stover |
Wheat straw |
Miscanthus sacchariflorus |
Rice straw |
Bagasse |
Yield stres s [pa] |
Flow stres s [pa] |
Yield stres s [pa] |
Flow stres s [pa] |
Yield stress [pa] |
Flow stress [pa] |
Yield stres s [pa] |
Flow stres s [pa]] |
Yield stres s [pa] |
Flow stres s [pa] |
Attrition milling (20∼25%w/w) |
8.2 |
8.2 |
4.8 |
8.6 |
82.0 |
91.0 |
12.6 |
30.1 |
4.4 |
10.7 |
Grinder milling (10%w/w) |
93.1 |
93.1 |
180.4 |
191.9 |
96.7 |
98.8 |
90.1 |
96.5 |
- |
- |
Hammer milling (10%w/w) |
63.5 |
63.5 |
3.0 |
19.7 |
81.9 |
90.9 |
- |
- |
96.1 |
98.2 |
Cutter milling (10%w/w) |
20.8 |
20.8 |
160.6 |
- |
23.0 |
25.8 |
58.5 |
66.5 |
13.7 |
32.8 |
[0060] From these results, it was confirmed that the herbaceous biomass slurry composition
treated by the attrition milling had significantly improved mixing and flow under
a high concentration substrate condition compared to biomasses that were treated with
conventional grinding methods such as grinder, hammer, and cutter milling. That is,
due to the remarkably low density characteristics inherent to the herbaceous system
when reacting with a liquid, herbaceous biomass cannot have a substrate concentration
that exceeds 10% (w/w), but when treated with the attrition milling, it was confirmed
that mixing and flow are possible under a high concentration substrate condition of
20% (w/w) or more so that reaction is possible.
[0061] From the above description, those skilled in the art will appreciate that the present
disclosure can be implemented in other specific forms without changing the technical
spirit or essential features. In this regard, the embodiments described above are
to be understood in all respects as illustrative and not restrictive. The scope of
the present disclosure should be construed that all changes or modifications derived
from the meaning and scope of the following claims and equivalent concepts rather
than the detailed description are included in the scope of the present disclosure.